This proposal details a methodological study into the synthetic applications of furan-carbonyl photocycloadditions. These studies serve two major purposes. First they would provide new information on the photocycloaddition reaction including the stereochemical consequences of what amounts to a threo specific aldolization process. Second, they would illustrate the design of systems which could fully exploit the usefulness of these reactions in the synthesis of a large body of biologically important natural products.